The Covid-19 vaccine offers strong protection against serious illness and mortality for at least six months after vaccination, according to evidence from the Health Information and Quality Authority (Hiqa).
The health authority has published three reviews on the duration of immunity after vaccination to inform the work of the National Advisory Committee on Immunization (Niac).
Studies focusing specifically on healthcare workers have shown levels of protection against serious illnesses similar to those seen in the general population.
While the jab provides solid protection for up to six months, there was less protection for some vulnerable groups.
Hiqa said some studies suggest there is waning protection, especially for the elderly and in people with immune disorders.
Hiqa added that it is difficult to determine whether reductions in protection are due to waning immunity, differences in exposure, increased transmissibility and / or vaccine escape from new variants, or a mixture of all of these factors.
“Despite the good protection offered by vaccination, national and international data indicate a higher risk of serious illness in the elderly and those with underlying illnesses,” said Dr Mark O’Loughlin, public health researcher at Hiqa.
“Given this and the lower potential vaccine response for these populations, any further reduction in protection would be of concern. “
Dr O’Loughlin urged people who have been offered a booster to get one.
Currently, healthcare workers, people 60 years of age or older, people living in nursing homes or long-term care facilities, and people over 16 with an underlying illness are offered a recall in Ireland.
“There is some uncertainty regarding protection after six months, particularly with regard to new variants of concern and the evolution of public health measures,” said Dr O’Loughlin.
“We encourage anyone who has been offered a booster dose to take advantage of it and protect themselves as much as possible. ”
Of the three reviews, the first looked at the duration of protective immunity after vaccination against Covid-19 in all populations aged 12 years and older.
The first update focused on healthcare workers, while the second update focused on people with underlying conditions.
The reviews identified more than 50 studies.